The e-retailer had previously committed $5 billion to the emerging market. Any extra capital would help stave off a threat from Walmart, which last month took a majority stake in Indian e-commerce giant Flipkart.

Citi Research last month estimated Amazon's India market to be worth $16 billion.

"Amazon is betting big on the India market. It is evident that after Walmart's acquisition of Flipkart, Flipkart's ability to increase market share and India presence will increase," an unnamed source told CNBC TV-18.

"Amazon has had its eyes and ears firmly on the ground and has been carefully planning its strategy. India is one of its fastest growing geographies and Amazon will not be left behind."